The good chip guide

British shoppers are now more likely to buy their potatoes in processed form than fresh from the greengrocers. But does this trend towards oven chips and waffles mean more bad news for the nation's waistlines? Not necessarily says Angela Dowden who offers a guide to the most popular pre-prepared varieties.

Oven Baked

Per 100g: 175 calories; 5.3g fat

These are just potatoes brushed with oil, and, because you bake rather than fry them, a medium portion contains less fat than a jacket potato with a knob of butter. A portion contains a third of the Recommended Daily Allowance of vitamin C (three times more than an apple) and more iron than two tablespoons of boiled spinach. 8/10

Oven Baked: Thin Cut

Per 100g: 230 calories; 8g fat

Thinner oven chips allows added brushed oil to soak into an increased overall surface area. So a portion can have as much fat as some fried chips. 5/10

Microwave

Per small box: 189 calories;

8.5g fat Fat and calorie-wise, these chips are somewhere between baked and fried. But they are made with just potatoes and vegetable oil so, despite their junk food persona, they are reasonably healthy.4/10

McCain's Mega Microchips

Per 100g: 160 calories; 5.7g fat

These contain additives not in standard micro chips because of their crunchy starch coating. Bigger chips mean less fat per 100g, but this is outweighed by a larger portion size.4/10

McDonald's Fries

Per 100g: 265 calories, 11.5g fat

Greasier than chips from a chip shop but not as high in fat as frozen chips you fry at home. McDonald's in America is changing the cooking oil so the chips have nearly 50 per cent fewer cholesterol-raising trans fats (one of the unhealthiest aspects of food commercially fried in hydrogenated oils).

A healthier oil is already in use in the UK, but the calorie content hasn't changed. Heavy handed salting means a large portion supplies 60 per cent of a woman's daily guideline salt intake. 2/10

Frozen Fried, thin cut

Per 100g: 273 calories; 13.5g fat

Frozen chips cool down the frying oil, so they don't seal quickly and consequently absorb more fat. But frozen chips are highest in vitamin C with up to 50per cent of the Recommended Daily Allowance in 200g. A portion also provides around 14 per cent of the recommend intake of iron. 2/10

Southern Style

Per 100g: 364 calories; 21.3g fat

The highest fat chips of the lot. The thin cut means there is maximum surface area to absorb more frying oil. Crinkle cut can be almost as bad as they also have more exposed surfaces. 1/10

Chip Shop

Per 100g: 239 calories; 12.4g fat

Not as high fat as you might think, but big portion sizes do nothing for your waistline.

Often low in vitamin C because of the time spent hanging around, and can also be high in trans fats. A study in the New England Journal of Medicine found these fats have a net effect on the ratio of bad-to-good cholesterol - twice as bad as that caused by saturated fat. 2/10

Depending on how you make them, these can be quite healthy. The key is to cook them in small batches using very hot oil and potatoes that are at room temperature. This allows the surface of the chip to be immediately sealed, so that less fat is absorbed. 6/10

Steak Chips

Per 100g (baked): 151 calories; 3.3g fat

Leaving the skin on makes these higher in fibre and B vitamins. Also particularly low in fat because of the chunky cut. The same doesn't apply to coated or fried wedges. 9/10

Bird's Eye Waffle Chips

Per 100g : 187 calories; 9.2g fat

Coated seasoned chips cut into waffle shapes and oven baked. They have twice as much fat as normal oven chips and include raising agents and starches. A small portion provides a fifth of a woman's maximum recommended salt intake. 4/10

Frozen Fried

Per 100g: 225 calories; 11.5g fat The healthiest of the supermarket fry chips - with fewer, bigger chips per portion, you get less surface area and reduced oil absorption. Good source of vitamin C, but still not as healthy as oven chips. 5/10